Starting resistance for motors.



No. 847,111. PATENTED MAR. 12;A 1907.

- H. G. REIST.

STARTING RESISTANCE FOR MTORS.

APPLICATION FILED JUNE 23.1904.

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EiINIIIIIIIIIIINIIHIHIIIIIIII JIJ/EPITDR: Henry G. Rei SC. bl

ITVIESSES:

PATBNTED MAR. 12, 1907.

H. G. RBIST. STARTING RESISTANCE POR MOTORS.

APPLICATION FILED JUNE 23.1904.

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lN/NTF l-Iem'mj Gli-eist. l1. Nuth..

M-rgls TW UNITED STATES PATENT OFFICE.

HENRY e. REisT, OE scHENEOTADY, NEW YORK, Assis-NOR ro GENERAL lELEcrRio COMPANY, A CORPORATION or NEW `YORK.

STARTING.' RESISTANCE Fon MOTORS;

Specification of Letters Patent.

l Patented March 12, 1907.

Application led June 23, 19Q4` Serial No. 213.782.

AT0 all 10h/mt it Trl/(Ly concern.- h

Be itknown that I, I-IE'NRY G. REIsT, a citizen of the United States, residing 4at of New York, have inventedcertain new and useful `Improvements in Starting Resistancesv fon-Motors, of which the following is a specifie'ation. p

My invention relates to alternating-current motorsof the inducti-on'type; and its object is to provide al novel arrangement of the starting .resistance and controllingswitch therefor. 4

It is Well understood that in order to give induction-motors a high starting torque it is necessary to Short-circuit the secondary coils at starting through resistances, which are ygradl'ially cut'out asa motor comes up to n order toY avoid sliding contacts, it f speed. is necessary to mount the resistances on the rotor. It 1s also necessary to provide a suitable switch for cutting out the resistance as a motor comes up to speed.

space and are unsuitable where important item.

By my invention I provide a very compact arrangement of the starting resistance and controlling-switch which'reduces to a minimum the space required for mounting the 'resistances and switch on the rotor.

My invention will best be understood by reference to the accompanying drawing, in Which- Figure 1 shows an induction-motor, partly in cross-section, arranged in accordance with my invention.` Fig. 2 shows an end view of the resistances and controlling-switches, and Fig. 3 is a diagram of connections.

In Fig.` 1, S represents the stator of an induction-motofcarrying the stator-coils s.

R represents the rotor carrying the rotorcoils 1*. B B represent resistances Winch are formed as bobbins, each comprising a thin Many of the. lforms of starting resistance that have been proposed heretofore occupy a considerable space is an strip of resistance material Wound on edge.

The strip is preferably Wound non-inductively in the Well-l, 1 .own manner by winding alternate sections in opposite irections. The resistance material is provided with` an vinsulating-coating which insulates adjacent turns from each other. This form of resistance unit is described in Patent No. 803,795, issued to G. E. Stevens November 7, 1905.

Each bobbin B is secured' to the rotor by. a

bolt b, this bolt being insulated from the resistance material. Therotor is .formed lwith an oii`set ilange which is secured to the shaft and supports the portion which carries the winding.` By. bolting-.the bobbins to this flange, as shown in the drawing, they are supported beneath the rotor-winding and do not increase the, width of'v the rotor. A ring bis clamped against the outer ends of the bobbins and takes up the centrifugal strain.

The rotor-shaft -A is hollowed out for a por-- tion of its length to receive a rod C, which is shown in Fig. 1 entering the left-hand end 'of shaft A. The rod carries a pin c, lwhich extends outward through a slot D in shaft A and carries a collar E. This construction is clearly shown in detail in Fig. 2. The collar i E carries a plurality of brushes e, which are all grounded on the collar orotherwise Velectrically connected to each other. These brushes bear on the-'outer surfaces of vthe- 4bobbins B. The outer surfaces of the bobbins are uninsulated, so that as `rod AC is pushed inward, moving the collar E toward the rotor-spider, the brushes efe, traversing the outer surface of the bobbins B, vary. the amount of resistance in the rotor-circuit.

The connections are shown diagrammatically in Fig. 3, in Which s representsthe statorcoils connected to the line-Wires 1 2 3. The

motor in vthis particular diagram isshown asA three-phase. The rotor-coils r are also shown A as three-phase, each phase being connected in series with a bobbin B by means-of the terminals N. (Shown in Fig. 2.) The three brushes e are shown electrically connected in Fig. 3, and. it is seen that as these brushes are moved toward the rotor the amount of resistance in the rotor-circuit is gradually reduced.

In order to hold the brushes in any given position and Ato prevent too rapid a movement of the brushes when manually controlled, I provide the notched key or rack F, secured to or let into theshaft D and adapted to be engagedV by a spring-pressed pawl f, carried by the collar E. The spring which controls` pawl f is given sufficient strength toA hold the collar Ein any desired position and loo to produce a step-bystep movement of the coldlar when -pushed inward or retracted by ro (l. i

y thereto, resistanoe-bobbins mountedon said movable collar surrounding vention, and I aim in the appended claims to cover all such modifications.

What I claim as new, and desire to secure by Letters Patent of the United States, is-

l. In a motor7 a member supporting the rotor-Winding and having a supporting oli'set llangeseeured to the shaft, 'a plurality of b'olts secured to said iiange and distributed around the shaft and extending parallel thereto, resistanoe-bobbins mounted on said bolts and insulated therefrom, a ring engaging the outer ends of said bolts and holdingr them against centrifugal strain, and axiallymovable contacts engaging the peripheries of said bobbins'. I y I 2. In a motor, a member supporting the rotor-Winding and'havin asupportin offset flange secured vto the sigiaft, a plura ity of bolts secured to said liange and distributed around vthe shaft land extending parallel bolts and insulated therefrom,v a ring engaging the outer ends of said bolts .and holding them against centrifugal strain, an axiallythe shaft, and i contacts carried by said collar and engaging the outer peripheriesoi said bobbins.

3. In a motor, resistances mounted on the rotor, axially-movable contacts adapted to engave said resistanoes, a notched rack on the s iaft, and a spring-pressed paw] carried by the movable contacts and engaging said rack.

4. In a motor, a Collar surrounding the shaft and axially movable thereon, Contacts carried by sa id collar, resistances mounted on the rotor and adapted to lze engaged by said contacts, a notched rack on the shaft. and a spring-pressed pawl carried by said collar and engaging said rack.

'5.a In a motor, resistanee-bobbins mountedonthe rotor With their axes parallel With the shaft, a collar' axially movable on the shaft, contacts carried by said collar and adapted to engage the peripheries of said bo bbins, a notched rack on the shaft, and a spring-pressed pawl carried by said Collar and engaging said rack.

vIn Witness whereof I have hereunto set my hand this 22d day'of J'une, 1904.

HENRY G. REIST.

Vitnesses:

BENJAMIN B. HULL, v HELEN ORFORD. 

